This same thing happened to me and its because there was a change to the function that writes up the Category picker on the form.
If anyone had followed the recommended steps to customize the form page, they will see this problem.
You can solve it by reverting back to the original form (remove the override from your theme folder) or replacing
<?php tribe_get_template_part( 'community/modules/taxonomy'); ?>
with
<?php tribe_get_template_part( 'community/modules/taxonomy', null, array( 'taxonomy' => Tribe__Events__Main::TAXONOMY ) ); ?>
I’ll also note that there are some structural changes to the html (including css class name changes) so any custom css overrides may need to be updated…
This is kind of annoying to have to go fix this stuff when there is a plugin update.